1. Field of the Invention
The invention relates in general to methods of manufacturing, more particularly, to methods of separating optical components formed on a substrate.
2. Background of the Invention
A variety of electrical and optical components are formed on substrates such as silicon and silica. A typical component manufacturing process involves etching the various parts of the components and interconnects onto the surface of a wafer. Ingots can be grown and several disc-shaped wafers are sliced from the ingot. Due to cost and fabrication time efficiencies, several devices are formed on a single wafer. After several components are formed on a wafer the components are separated.
Conventional methods of separating the components include sawing, mechanically cutting, and using a laser or milling machine. Often the edges of the separated components are further finished by polishing. Conventional methods, however, have several disadvantages. For example, vibrational and thermal and other stresses caused by cutting and polishing fatigue the material and result in less than optimum performance of the components. Often the stresses of the separation process do not affect performance of the component until a period of time has passed and the stress fractures and fissures have propagating from the edge of the substrate to critical components.
Optical components using conventional separation techniques are particularly susceptible to the problems discussed above. Due to the small wavelength of light, the performance of optical components is significantly affected by imperfections such as fractures or fissures. Further, the interfaces of optical components such as facets are often formed by cutting and polishing. In addition to the problems discussed above, the cutting and polishing of an optical interface can result in an interface with poor transmission and reflective characteristics.
Therefore, there is a need for a method for separating components formed on a substrate.
The invention relates to a method of separating optical components. The method includes obtaining a substrate structure having a plurality of optical components formed on the substrate structure. The method also includes performing a separation etch on a separation region of the substrate structure. The separation region is selected such that separating the substrate structure at the separation region separates at least one of the optical components from the other optical components.
Another embodiment of the method includes obtaining a substrate structure having an optical component formed on the substrate structure. The method also includes performing a separation etch on a separation region of the substrate structure. The separation region is selected such that separating the substrate structure at the separation region trims the substrate structure away from the optical component.
In some instances, the component(s) includes a waveguide and the separation etch is performed so as to form at least a portion of a facet on the waveguide. The separation etch can optionally be performed so the facet is angled at less the ninety degrees relative to a direction of propagation of light signals traveling along the waveguide.
The invention also relates to a substrate structure. The substrate structure includes a plurality of optical components positioned on the substrate structure. A groove is formed on the substrate structure. The groove is positioned such that separating the substrate structure along the groove separates at least one of the optical components from the other optical components.
Another embodiment of the substrate structure includes an optical component positioned on the substrate structure. A groove is formed on the substrate structure. The groove is positioned such that separating the substrate structure along the groove trims the substrate structure away from the optical component.
In some instances, the groove is positioned adjacent to a facet of one or more waveguides positioned on the optical component(s). The facet can optionally be angled at less than ninety degrees relative to a direction of propagation of light signals traveling along the waveguide.